The present invention relates to an underwater weighing apparatus useful in determining the body density of the person being weighed.
It is medically useful to estimate the body fat content of a person as the relative amount of their body fat changes due to diet, exercise, disease or aging. It is well known in the art to weigh persons under water as a means of determining the body fat content of the person being weighed. Body fat is less dense than water whereas the fat free portion of the body (including muscle, bone, etc.) is more dense than water. By weighing a person who is totally immersed in water, conclusions can be drawn as to the relative amounts of body fat of the person. It has been generally accepted that the most accurate way to assess the relative fat content of a person is to measure the overall body volume by means of water displacement, correct for the volume of gas in the body, and calculate the body density by dividing the mass of the body by its (corrected) volume.
Conventional methods of weighing persons under water generally require a pool or specially constructed immersion tank, sufficiently large to accommodate a person seated or kneeling on a weighing chair or platform, and containing a sufficient amount of water to totally immerse the person being weighed. Such conventional methods involving pools generally require a weighing apparatus to be suspended from the ceiling, or from an overhead boom, or otherwise attached to the pool. The means of attaching such weighing apparatuses are cumbersome and required rigid, fixed attachment to the ceiling of the room in which the pool is located or the sides or bottom of the pool. Since a variety of sizes and shapes of pools or tanks have been constructed for the purpose of weighing persons under water, each pool or tank required a uniquely designed weighing system which was more or less permanently fixed in place and not easily moved. As a result, conventional immersion tanks and underwater weighing systems are expensive and usually found only at universities where research on the relative amount of body fat is conducted.
It is desirable to have a simple, light-weight and portable apparatus which can be used in conventional pools or tanks of water.